Microsoft is restoring some old features and rolling out new ones in a bid to reignite interest in its flagship operating system

Other new features in Windows 8.1

• The ability to take Skype calls or pictures from the Lock screen without having to log in.

• More tile-size options for the Start screen.

• A photo editor.

• Improvements in first-party apps that come with Windows.

• More “snap” view sizes to allow viewing of multiple apps on screen at the same time.

• The ability to roam your settings across different Windows 8.1 devices, thanks to use of the cloud.

• Internet Explorer 11, which is expected to have faster page-load times.

Microsoft is trying to fix what it got wrong with its radical makeover of Windows. It’s making the operating system easier to navigate and enabling users to set up the software so it starts in a more familiar format designed for personal computers.

The revisions to Windows 8, revealed Thursday, will be released later this year. The update — called Windows 8.1, which will be shipped free to Windows 8 customers — represents Microsoft’s concessions to longtime customers taken aback by the dramatic changes to an operating system that had become a staple in households and offices around the world during the past 20 years. Research group IDC has blamed Windows 8 for accelerating a decline in PC sales.

With the release of Windows 8 seven months ago, Microsoft introduced a startup screen displaying applications in a mosaic of interactive tiles instead of static icons. The shift agitated many users who wanted the option to launch the operating system in a mode that resembled the old setup. That choice will be provided in Windows 8.1.

However, Microsoft isn’t bringing back the start menu on the lower left corner of the screen. Windows has offered the button for accessing all programs and settings on every previous version of the operating system since 1995. Microsoft believes the startup screen replaces the need for a button, but its omission has ranked among the biggest gripes about Windows 8.

Microsoft is hoping to quiet the critics by offering a stripped-down version of the start button — it will resurrect an omnipresent Windows logo anchored in the lower left corner that will appear anytime the cursor moves to that corner.

Users will also be able to ensure their favorite applications, including Word and Excel, appear in a horizontal tool bar next to the Windows logo. Accessing apps outside the toolbar will still require using the tiles or calling them up in a more comprehensive search engine included in the Windows 8.1 updates.

The Redmond, Wash., firm announced its plans for Windows 8.1 in early May, but it didn’t offer details about what it will include until Thursday. It will provide a more-extensive tour of Windows 8.1 and several new applications built into the upgrade at a conference for programmers in San Francisco, scheduled to begin June 26.

Antoine Leblond, a Microsoft executive who helps oversee the operating system’s program management, said the ability to start PCs in the more familiar format is meant to ease the “cognitive dissonance” caused by Windows 8.

Gartner analyst Carolina Milanesi predicted the desktop option will spur more sales of Windows 8 computers. “Some people were getting fixated” on the desktop issue, Milanesi said. “This may cause more people who felt uncomfortable with Windows 8 to take a second look.”

Microsoft made the dramatic overhaul to Windows in an attempt to expand the operating system’s franchise beyond personal computers that rely on keyboards and mice to smartphones and tablet computers controlled by a touch or swipe of the finger. But Windows 8 has been widely panned as a disappointment, even though Microsoft says it has licensed more than 100 million copies so far.

Microsoft views Windows 8.1 as more than just a fix-it job. From its perspective, the tuneup underscores Microsoft’s evolution into a more nimble company capable of moving quickly to respond to customer feedback while also rolling out more innovations for myriad Windows devices — smartphones, tablets or PCs.

“Windows 8 has been out long enough for us to take stock of where things are going and what we need to do to move it forward,” Leblond said.

It’s crucial that Microsoft sets things right with Windows 8.1 because the outlook for the PC market keeps getting gloomier. IDC now expects PC shipments to fall by nearly 8 percent this year, worse than its previous forecast of a 1 percent dip. IDC also anticipates tablets will outsell laptop computers for the first time this year.

The growing popularity of tablets is now being driven largely by less expensive devices with 7- and 8-inch display screens. Microsoft built Windows 8 to primarily to run on tablets with 10-inch to 12-inch screens, an oversight that Leblond said the company is addressing by ensuring Windows 8.1 works well on smaller devices.

If Windows 8.1 doesn’t stimulate more sales of PCs and tablets running on the operating system, it could escalate the pressure on Microsoft CEO Steve Ballmer. Although the company’s revenue and earnings have steadily risen since Ballmer became CEO 13 years ago, Microsoft’s stock performance has lagged other technology companies. Investors, though, appear to be more optimistic about Ballmer’s strategy. Microsoft’s stock has risen by about 25 percent since Windows 8’s release last October, outpacing the 17 percent gain in the Standard & Poor’s 500 index during the same period.

Microsoft’s stock gained 15 cents Thursday to close at $35.03.

The upcoming changes to Windows 8 are as much about reassuring the PC manufacturers and other device makers who license the operating system as appeasing consumers, Forrester Research analyst Sarah Rotman Epps said.

“The messaging is really directed at people in the industry,” she said. “The original launch (of Windows 8) seemed incomplete and Microsoft is trying to address that now.”